<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>两列布局解决方案2-float+margin(fix)</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    #left{float:left;width:200px;height:400px;background-color: green;}
    /*  左定宽  +  右自适应 =  calc(100% - 200px)  
    1.flex:1
    2.grid: auto
    3.定位 - 方位同时设置
    .....

    100%  - 200 px 
    ....
    */
    #right-fix{float:left;background-color: blue;}
    #right{height:600px;}
    #inner{
      width: 300px;
      height:300px;
      background-color: gray;
      clear: both;
    }
  </style>
</head>

<body>
  <div id="left"></div>
  <!-- 为自适应元素定位父级元素 -->
  <div id="right-fix">
    <div id="right">
      <div id="inner"></div>
    </div>
  </div>


</body>

</html>